Applications for pointing or orienting devices are often limited by the speed and precision of the mechanism, especially over large angles. Gimbals are frequently used in two degree-of-freedom (DOF) pointing applications. Since these are serial mechanisms, the base actuator must provide sufficient torque to move the second motor as well as the end-effector. Parallel pointing devices distribute the load among the actuators in a closed kinematic chain, allowing for smaller actuators and providing higher operation bandwidth.
Parallel mechanisms have been developed for high-performance camera orientation and vibration isolation. As an example, the Agile Eye is a 3-RRR spherical parallel wrist in which all pairs of adjacent joint axes are orthogonal (U.S. Pat. No. 5,966,991). Many applications are limited by the speed and precision at which current pointing mechanisms are capable of operating, especially over larger angles. For example, laser applications include precision pointing for communications, light shows, target illumination, etc., and camera and mirror pointing uses require image jitter reduction for land, sea, air, and space platforms.